Food changes during Processing

Humans have learnt to cook, to broil, to steam, to bake, to roast, to fry, to smoke and to barbeque food on burning coal, wood or oil, transmitting heat through metal surface contact, by convection, by radiation, using steam or gas or fluids.

To these can be added in modern times, to pasteurize (UHT) treatments heating with infrared, microwave and ohmic heating.

Chemical changes that occur during food processing are numerous, and they can be desirable, undesirable, of questionable consequence or a combination thereof.

Thermal treatment lead to desirable changes, such as protein coagulation, starch swelling, textural softening and formation of aroma components and these changes can influence sensory properties, functional properties and/or nutritive value.

Changes induced by processing in food proteins relate mainly to their denaturation, binding of flavor-active and lipid oxidation products to them and modifications brought about intentionally by derivation and enzymatic treatment.

Among lipid constituents of foods, both polar and non-polar components are affected by processing. While many of the changes that occur in food lipids are experienced during their production, many of these effects are system-dependent.

Carbohydrates also undergo changes during milling, cooking, drying, freezing and storage. Carbohydrates present in food are either in the polymeric, oligomeric or simple form. Many of the characteristics of carbohydrates in foods and their physio-chemical changes during processing are dictated by structural characteristics. Complex carbohydrate constituent of foods and the source material from which they are derived also affect many of their properties.

However undesirable changes also occur, such as losses of vitamins and minerals, formation of thermal reaction components of biopolymers, and in minimal processing terms, losses of fresh appearance, flavor and texture.

Yet gradually some ill effects of processing on food compositions and wholesomeness started to come to light, for example the Maillard interaction between carbonyl and amino compounds and their subsequent cyclization and polymerization, caramelization reactions that lead to the formation of heterocyclic compounds, polycyclic aromatic molecules, nitrosamine and such other toxic, carcinogenic and mutagenic molecules during processing.

Although these are known to be produced in trace quantities the consumer has become aware of the lurking danger.

Food processing can result in several changes and advantages, some of which are substantial:
*Lessened hazards from microbial pathogens
*Lessened spoilage (microbial, enzymatic)
*Inactivation of heat-labile, anti-nutritional substance
*Increase a variety of foods, some with enhanced sensory properties - bakeries, confectionary, meat analogs, fermented foods.
Food changes during Processing

Chemical properties of coconut oil

Coconuts, form the Cocas nucifera lam, are dehusked before cracking the nut to drain away the coconut water.  Coconut palm is productively gown within 20° north and south of the equator, especially along coastal areas.

Traditionally, coconut oil is extracted from copra by crushing in an expeller, followed by solvent extraction to recover the residual oil from the cake.

The oil content ranges from 34 to 45 % in the ripe endosperm of coconut and from 60 to 77 per cent in well dried copra.

The oil content is influenced by the water content in the nut, stage of maturity and the type of coconut variety.

The oil contains predominantly triglycerides with 86.5% saturated fatty acids. This makes the crude oil very stable against oxidation. They consist of C12, C14 and C16 with C12 predominating.

Others are 5.8% monounsaturated fatty acids, and 1.8% polyunsaturated fatty acids.

Of the saturated fatty acids, coconut oil is primarily 44.6% lauric acid, 16.8% myristic acid and 8.2% palmitic acid, although it contains seven different saturated fatty acids in total. Its only monounsaturated fatty acid is oleic acid while its only polyunsaturated fatty acid is linoleic acid.

Coconut oil is composed of a special group of fat molecules known as medium chain fatty acids (MCFA) which contains 8 to 12 carbon chains.  The sum of MFCA in coconut oil is 62%, which makes the oil the richest source of MCFA among vegetable oil.

Medium –chain fatty acids in coconut oil are broken down and used predominantly for energy production and thus seldom end up as body fat or as deposit in arteries or anywhere else.
Chemical properties of coconut oil